A portable terminal means communication equipment capable of exchanging calls and data while moving. Recently, portable terminals implement various useful functions in line with the era of digital convergence.
For example, the user may use audio on demand (AOD) service and video on demand (VOD) service using the portable terminal, or make video phone calls where the person making the call and the person receiving the call can see each other's face while making the phone call, or download games and play them. That is, the portable terminal is not used restrictively in the field of voice communication equipment any longer.
As the portable terminal is implementing more functions, users feel a need to control the portable terminal more quickly and conveniently. Accordingly, portable terminal manufacturers are providing a display unit implementing a touch screen function (hereinafter, “touch screen display unit”) to the users.
Meanwhile, the touch screen panel used in the portable terminal may be a capacitive overlay type, resistive overlay type, surface acoustic wave type, transmitter type, infrared beam type, etc. Among the various types of touch screen panels, the capacitive overlay type is mainly used in portable terminals.
As can be seen in FIG. 1, the touch screen panel of the capacitive overlay type includes a window 1 made of PET, which is a dielectric or an insulator, an icon unit 3 covering a silver paste electrode 2 combined later by being coated at a lower edge of the window 1 and printed with a logo, etc., a PC sheet or glass 5 combined with the window 1 with double-sided tape 4, a dielectric film 6 made of a PET material combined in a lower surface of the glass 5 with double-sided tape 4, an ITO coating layer 7 deposited on a part sensing touch at an upper part of the dielectric film 6 with a transparent conductive material such as ITO, etc., a silver paste electrode 2 combined with an edge of the ITO coating layer 7 to deliver an electric signal to a control unit, and an LCD 9 attached on a lower surface of the dielectric film 6 with double-sided tape 8.
However, since the conventional touch screen panel of the capacitive overlay type uses three double-sided tapes (OCA tape: 4, 8) during the depositing process, there are disadvantages that a lot of defects occur because of the foreign substances and gas bubbles generated during the process of attaching double-sided tape when manufacturing a patch display unit with the current process. Also, the defect rate of the process is high due to the contraction of the double-sided tape and lump of the adhesive.
Accordingly, as shown in FIG. 2, Korean Patent Laid-Open No. 10-2010-0065486 discloses a touch screen panel structure of a capacitive overlay type, which improves the strength of the display unit by using a window and coating a CNT material by a screen method, and reducing defect rate by reducing the process of attaching double-sided tape.
That is, the touch panel includes a high strength plate 18 made of a high strength material such as acryl or window, etc., a UV coating layer 22, an icon unit 20, a CNT coating layer 16, a silver paste electrode 14, a ground electrode 24, and an LCD 10.
However, since the touch panel configured as above includes a plurality of layers, defects occur frequently during the manufacturing process, and there is difficulty in satisfying the consumer's desire to reduce the thickness of the portable terminal.